Troubleshooting - Haze (unexpectedly hazy beer)
Is your beer hazy, when it was intended to be crystal clear?
Haze can be caused by many different factors in your beer, which makes this a difficult property to troubleshoot.
Mitigating haze comes down to understanding what type of haze you have in the beer, and the ionic charge of the haze-forming particles (whether yeast, protein, polyphenols, or starch).
First, we suggest doing some simple tests to determine what type of haze you have.
Determining What Type Of Beer Haze You Have
1. Find out if it is yeast causing the haze. If you have a microscope, check the beer to see if there is a high concentration of yeast in suspension. To further confirm the haze is from yeast cells in suspension, test adding some positively charged finings (such as isinglass or gelatin, properly dissolved) to a glass of beer and letting it sit covered overnight.
2. Find out if it is protein haze. Add a few small drops of caustic (NaOH) to a glass of beer (make sure to label it "do not drink" and dump promptly after the test, and take all relevant safety precautions when handing caustic). If it clears after 10-15 minutes, you are dealing with protein haze.
3. Find out if it is starch haze. Add a few drops of iodine to a beer sample (similar to the iodine starch test for mash conversion). If it turns blue/black, you have starch haze.
4. Find out if it is chill haze. Bring a sample of beer up to room temperature. If it clears (and there wasn't a lot of yeast in suspension), you have chill haze.
Note that many haze issues are a result of several of these contributing factors. Performing these simple tests will help you find out which type of haze you are dealing with. Even if it is multiple types (E.g. yeast haze plus chill haze), there are potential interventions to solve the problem.
If the results from all those tests are inconclusive this means you likely have a complex haze like dry hop mediated haze which can itself be a combination of protein and polyphenol haze. In the case of some hard-to-remove hazes, a proline endoprotease enzyme can be beneficial.
Below we have listed typical root causes and proposed solutions for different types of haze. Ultimately it is better to address the root-cause of the issue.
Beer Haze Mitigation Strategies
| Type of Haze | Root Causes | Solutions |
| Yeast | Poor flocculation or growth. Often due to insufficient magnesium or zinc or poor wort oxygenation. Sometimes due to selecting a poorly flocculent yeast. | Ensure wort has adequate magnesium and zinc. Ensure yeast nutrition is provided (e.g. Yeast Lightning). Some post-fermentation finings can be effective. |
| Protein | Insufficient kettle fining/sedimentation/whirlpool leading to excessive protein in the beer. | Use kettle finings such as Whirlfloc/carrageenan. Avoid mash pH too high or low (target 5.3-5.5). Post-fermentation finings can be effective. |
| Starch | Incomplete starch conversion in the mash. | Ensure complete starch conversion in the mash with the iodine test. Avoid mash temperature and pH too high or low. |
| Chill Haze (subset of protein haze) | Insufficient kettle fining/sedimentation/whirlpool leading to excessive protein and polyphenols in the beer. | Post-fermentation finings can be effective at reducing chill haze. Avoid mash pH too high or low (target 5.3-5.5). |
Beer Haze Removal Strategies
Now that you have identified the type of haze, you have the information needed to start addressing the issue and clearing your beer. One of the most important factors in beer clarification is the ionic charge of the haze particles in question.
The role of ionic charge
Ionic charge plays a big role in successful beer clarification. As a general principle, you need to use positively charged finings (such as gelatin, isinglass, etc) to sediment negatively charged particles (such as yeast). On the other hand, use negatively charged finings (such as Whirlfloc, carrageenan, etc) to sediment positively charged particles (such as proteins and polyphenols).
Other finings that are silica-based or PVPP-based will have variable impacts on different types of haze. Consult your finings supplier for usage instructions and additional guidance.
Types of fining agents and their charge
| Fining Agent | Charge | Category |
| Gelatin, Isinglass | Positive | Proteinaceous |
| Bentonite, Tannins, Silica (eg Biofine, Protosol) | Negative | Non-Proteinaceous |
| PVPP, carbon | Neutral | Non-Proteinaceous |
Haze troubleshooting questions (for beers that shouldn't be hazy)
Q1: Have you recently changed malt supplier, malt type, or malt lot? What is the specific brand of base malt you are using?
Malt variability as a result of agriculture and processing can lead to differences in haze formation.
Q2: What is your water profile and which specific water salts are added to the water and when?
Insufficient zinc and magnesium can cause yeast growth and flocculation problems.
Q3: What is your mash pH and wort pH?
We recommend a mash pH of 5.3-5.5 in order to promote optimal enzyme activity. Reducing wort pH to 5.0-5.3 prior to the whirlpool will aid in cold break sedimentation and reduce the amount of protein and polyphenol in solution.
Q4: How long did the beer take to finish fermenting (reach FG)?
A slow fermentation indicates upstream yeast health issues which might lead to poor flocculation.
Q5: Are you adding any yeast nutrients? If so, which nutrients, dosing rate, and when do you add them?
Yeast health has a lot of impact on haze. Insufficient nutrition can cause poor flocculation or growth. However, even Hazy IPAs benefit from nutrients!
Troubleshooting yeast haze (yeast is not flocculating)
Potential root causes of yeast haze:
- Insufficient Magnesium and/or Zinc causing poor yeast growth and flocculation. If the yeast does not have enough magnesium, growth will be restricted which can reduce the number of cells able to "collide" and form floccs that settle out in the beer. If the yeast does not have enough zinc, growth can be restricted and flocculation behaviour can change. This can also be caused by excessive calcium. Solution is to increase magnesium and zinc in the wot.
- Insufficient positively charged particles in the fermentation (e.g. cold break). A small amount of trub in the wort can help bind to yeast and help form yeast floccs since yeasts are negatively charged particles. If trub is aggressively removed, sometimes this results in poor residual yeast flocculation. Solution is to reintroduce a small amount of trub to see if this helps.
- Contamination impacting yeast flocculation. We have seen some cases where contamination by wort spoilers or lactic acid bacteria can cause issues with yeast flocculation post-ferment, even if sensory issues do not arise in the finished beer. In this case, it is important to check the wort for wort spoilers and check finished beer for residual contamination. Root causes include buildup in plate heat exchangers and cracks/defects harbouring contamination inside brewery transfer hoses (especially if they are more than 2 years old). On fermentation vessels, sample valves and valve seats are a common potential source of contamination. Solution is a microbiological QC audit.
- Mutation/phenotypic drift. Yeast mutation typically takes multiple generations to occur, but this is also a possible root cause of yeast haze issues if the yeast has been repitched for many generations (>10). The solution here is to return to a new yeast stock.
Follow-up questions to consider:
1. Do you add any type of yeast nutrient to your wort?
2. How much trub carryover do you get in this wort? Have you recently been reducing trub carryover or implementing flotation, cold setting, or trub shaving practices?
- How old are your plate heat exchanger and brew hoses? Has your wort and beer been microbiologically tested recently?